Found a small metal band saw at a pawn shop.
Old, but does not look like it has worked too hard.
Paid R800 for it ($70, £50 , €55)
Seems I might have found why it is so cheap. it is cutting skew in the saw axis plane.
I have watched all You Tube videos in the topic and have cleaned, deburred the slots and replaced the worn washers with thick new ones, but still...about 1.2 mm on a 50mm cut.